A substance formed when two or more elements are mixed together without any chemical reaction is known as:
A) Atoms
B) Mixture
C) Molecule
D) Compound

Hint: Chemical reaction is a process in which one or more substances, the reactants are converted to one or more different substances, the products. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

Complete Step by Step Solution: An atom is the smallest unit of an ordinary matter that forms a chemical element. Every solid, liquid, gas and plasma are composed of neutral or ionized atoms.
> A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charges.
> A compound is a substance formed when two or more chemical elements are chemically bonded together.
> In chemistry a mixture is a material made up of two or more different substances which are physically combined. A mixture is a physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspension and collisions.
> In chemistry when two or more substances mix with each other without participating in chemical changes, the resultant substance is a mixture.
> The result formed due to the combination of substances does not lose its individuality nor are they combined chemically. Mixture is a material substance made up of two or more different substances which are mixed but are not chemically combined with each other.

So, hence from the above explanation we can say that the correct answer is B. i.e. Mixture.

Note: Mixtures are the product of mechanical blending or mixing of chemical substances such as elements and compounds. Mixtures can be heterogenous or homogenous in nature.